Deproteinization of Natural Rubber Using Protease Immobilized on Epichlorohydrin Cross-linked Chitosan Beads

Abstract

Deproteinization of natural rubber using an alkaline protease from Bacillus sp. immobilized on cross-linked chitosan beads is reported. Conditions were identified for attaining a high activity of the immobilized enzyme on the beads. The optimally produced enzyme beads were then used to establish the conditions for effective deproteinization of natural rubber. A two-level full factorial design was used to quantify the main effects and the interaction of the factors influencing the formation of the catalytic beads and the rubber deproteinization process. Results showed that by using the optimal deproteinization process, the total nitrogen level in the rubber was reduced from 0.35% to 0.013% w/w, or a >96% nitrogen removal. In contrast, the urea method of deproteinization achieved a lower nitrogen removal of <86%.The immobilized protease could be used for at least five repeated deproteinization cycles without losing more than 10% of the initial enzyme activity.

Immobilization of halophilic Bacillus sp. EMB9 protease on functionalized silica nanoparticles and application in whey protein hydrolysis

“…This explains the gradual loss in activity of enzyme when crosslinked with higher amounts of glutaraldehyde. Contrary to this, glutaraldehyde at even 6 % has been used for efficient crosslinking [18]. Cysteine protease, procerain B immobilized on glutaraldehyde activated carbon showed concentration dependent increase in immobilization efficiency from 58 to 84 % as concentration of crosslinker increased from 1 to 4 % [11].…”

“…Recently attempts to immobilize protease on TiO 2 , magnetic, bimetallic Ag-Au, silica nanoparticles have also been successful [14][15][16]. The immobilized preparations have also been documented for their use in development of protein hydrolysates [17], deproteinization of rubber [18], chitosan depolymerization [19], as detergent additive [16], transesterification and peptide synthesis in organic solvents [20,21].…”

Study on Preparation of Immobilized Alkaline Protease and Its Performance

“…[14] So, the conclusion can be drawn that when the temperature is 25°C, the amount of enzyme is 500µl, the glutaraldehyde concentration is 1%, the crosslinking time is 4h ， the adsorption time is 1h, and pH is 8, the effect of enzyme immobilization reaches the maximum. [15] Hydrolysis Result The sludge is hydrolyzed by immobilized enzyme under the best reaction situation. The test result is as follows: Here is the reason for the result: Sludge floc is fractured due to the effect of immobilized enzyme.…”

Optimal conditions for deproteinizing natural rubber using immobilized alkaline protease

“…Rubber deproteinization methods include treatment with enzymes, urea, surfactants, and acids and alkalis . Proteolytic enzymes remove proteins by cleaving them into small peptides . Urea and surfactants denature proteins to facilitate their removal by washing.…”

“…Current enzymatic treatments use soluble enzymes that are lost after a single use. An alternative is to use enzymes immobilized on polymer beads because a bead‐bound enzyme can be easily recovered and reused . In principle, good contact between the proteins on the NR particles and the surface immobilized enzyme on beads is feasible as the rubber particles are extremely small (100 nm to 2 µm) compared with the beads …”